1. Field of the Invention
The present invention relates to a liquid jet recording apparatus such an ink-jet recording apparatus or the like.
2. Description of the Prior Art
Ink-jet recording apparatuses are being highlighted as a new recording technology since they have advantages such that the direct recording is possible and the color recording is easy and that the noise is so low to be ignored, etc. In particular, an ink-jet recording apparatus of the on-demand type is cheap and can be miniaturized, so that it is becoming a central technology in the full-color printer technologies which are recently being highlighted.
However, the conventional recording apparatuses of this kind have drawbacks such that the ink supply system to ink jet heads is complicated and that the ink viscosity increases due to the evaporation of volatile material in the ink at the point of the head, so that it is difficult to maintain stability of ink emission.
Various types of means have been conventionally proposed as the ink supply system and a typical means has a constitution whereby an ink tank and a head are connected by a flexible tube; the other one has a constitution such that an ink tank is mounted over a head carriage and the ink tank and the head are directly coupled. However, the former means causes a problem on durability of the tube itself since the tube is pulled in association with the movement of the head upon recording. In addition, due to the load variation in association with the movement of the tube, many drawbacks are caused: namely, (i) instability in the carriage advance, i.e., shift of a recording point; (ii) instability in the ink emission due to the variation in resistance to a flow through the tube and to the incomplete ink supply because of the mixture of air bubbles into the tube, and (iii) there are many limitations regarding the design to hold the good positional relation between the head and the ink tank, so that the optimum design of the equipment becomes difficult, etc. On the other hand, the latter means has drawbacks such that the load of the carriage motor increases since the ink tank which contains a sufficient quantity of ink for the recording is mounted over the head carriage, so that this causes the whole equipment to be enlarged in size and to be increased in cost, and that the user's hand and the equipment may become dirty because of the ink leakage and the like when an ink cartridge is exchanged. These drawbacks will be further remarkable in the apparatus of a constitution which holds a plurality of kinds of inks having different ink densities for the purpose of improvement in picture quality.
On the other hand, as means for preventing the blinding, there have been proposed capping means for preventing the dryness of the head point, means for emitting the ink from the point, and the like. These means can present the effects for this purpose. However, in the case where these operations are manually done, its operability is inferior and there is also a drawback such that if the user forgets to cap, the ink emission may become instable, and the like. In case of emitting the ink from the head point, since the residual ink in the ink tank is reduced in association with an ink quantity to be emitted, it is necessary to additionally equip particular means for sensing the ink remainder, and these means have to be provided further individually from the ink supply system; therefore, there is a drawback such that it causes the equipment to be increased in both size and cost.
Moreover, there is also a drawback such that the meniscus moves backward due to the inadequate outflow of the air at the head point when capping, or the like, so that the ink emission becomes instable.